CN100394294C

CN100394294C - Liquid crystal display device

Info

Publication number: CN100394294C
Application number: CNB2005101073829A
Authority: CN
Inventors: 鎌田豪; 仲西洋平; 上田一也; 吉田秀史; 津田英昭
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2004-12-27
Filing date: 2005-12-26
Publication date: 2008-06-11
Anticipated expiration: 2025-12-26
Also published as: CN1800956A; JP2006184516A; KR100817193B1; KR20060074886A; KR100864265B1; JP5090620B2; CN101299123A; KR20070057107A; US20070013633A1; TWI310170B; CN101299123B; TW200703192A; US7692674B2

Abstract

The invention relates to a liquid crystal display used in a television receiver or a display section of an electronic apparatus and provides a liquid crystal display having a wide viewing angle and high viewing angle characteristics. The visual angle characteristic on a low gradation side is improved by a capacity coupling HT method (black triangular marks). The visual angle characteristic on an intermediate gradation to a high gradation side is improved by a driving HT method (black square marks). The improvement effects of both HT methods are added together by combining the capacity coupling HT method with the driving HT method to drive the liquid crystal, and the visual angle characteristic of the liquid crystal display device is improved in the wide range from the low gradation to the high gradation (round marks).

Description

Liquid crystal indicator

Technical field

The present invention relates to use liquid crystal indicator at the display part of televisor and electronic equipment.

Background technology

Figure 22 A and Figure 22 B represent MVA (Mult-domain Vertical Alignment; Multi-field homeotropic alignment) example of the structure of the vertical alignment-type liquid crystal display panel of mode.Figure 22 A schematically shows the cross-section structure of display panels 101.Figure 22 B is illustrated in the structure of pixel of the display panels 101 of the MVA mode of seeing display frame on the normal direction.Shown in Figure 22 A and Figure 22 B, display panels 101 has the TFT substrate 102 of formation thin film transistor (TFT) (Thin Film Transistor:TFT) 110 grades and forms common electrode and the subtend substrate 103 of color filter (CF) layer (not shown).Two blocks of peripheral encapsulants 105 of substrate 102,103 usefulness are fitted.Again, at 102,103 sealing liquid crystal layers 104 of two substrates.The interval of regulation is kept in space (cell gap) between TFT substrate 102 and the subtend substrate 103 with liner 106.This cell gap utilizes the overshooting shape liner to replace liner 106 sometimes, keeps predetermined gap.TFT substrate 102 and with the face of the opposition side of the subtend of subtend substrate 103 on, polarization plates 107 is disposed at for example intersects on the Nicol prism respectively.On TFT substrate 102, form the installation terminal 108 of installation liquid crystal drive with IC (not shown) again.

Shown in Figure 22 B, TFT substrate 102 has the grid bus 112 that extends to form in the drawings the left and right directions and intersect the drain electrode bus 111 that extends to form on the above-below direction in the drawings across dielectric film on grid bus 112.Crossover location at double bus 111,112 nearby forms the TFT110 that pixel drive is used.The part of grid bus 112 plays a role as the gate electrode of TFT110.The drain electrode of TFT110 (D) is electrically connected in drain electrode bus 111.The source electrode of TFT110 (S) is electrically connected the pixel electrode 109 that forms on the pixel region that double bus 111,112 delimited.Pixel region is crossed in formation, with the grid bus 112 storage capacitance bus 117 that extend arranged side by side.Store on the capacitance bus 117 and on each pixel, form storage capacitance electrode (target) 116 across dielectric film.Utilize and store capacitance bus 117, store capacitance electrode 116 and form storage capacitor C s at the dielectric film that is clipped in therebetween.

On pixel electrode 109, form the slit 114 that passes electrode material.Form wire projection 115 in subtend substrate 103 sides.The orientation limitations of the direction under slit 114 and wire projection 115 are toppled over as the liquid crystal molecule (not shown) that is limited in liquid crystal layer 104 when applying voltage works with member.Utilize slit 114 and wire projection 115 zonings in the pixel region, make liquid crystal molecule swing to four direction.Because liquid crystal 103 is swung to four direction, compares with the liquid crystal indicator of only toppling over to a direction, makes the deflection equalization at visual angle.By means of this, viewing angle characteristic improves significantly.Such technology is called as the orientation cutting techniques.

Figure 23 A～Figure 23 C schematically shows the cross-section structure of the liquid crystal indicator of the MVA mode of using the orientation cutting techniques.Figure 23 A represents that liquid crystal layer 104 does not apply the state of voltage.The state of representing to apply on the liquid crystal layer 104 voltage at Figure 23 and 23C.In Figure 23 A and 23B, be formed on two substrates of subtend substrate 103 that forms common electrode 118 and vertical orientation film 119 in order and the TFT substrate 102 that forms pixel electrode 109 as the wire projection 115 of orientation limitations with member.Among Figure 23 C, only be located at TFT substrate 102 sides with the slit 114 of member as orientation limitations.But the situation (not shown) of only establishing wire projection 115 on a side substrate is arranged also.

Shown in Figure 23 A, when not applying voltage, liquid crystal molecule 120 is vertical orientated in fact on the real estate of TFT substrate 102.When 102,103 of two substrates apply voltage, shown in Figure 23 B, the direction of toppling over according to the shape of wire projection 115 decision liquid crystal molecule 120.And for example shown in Figure 23 C, in the structure that forms slit 114,, also, determined the direction that liquid crystal molecule 120 is toppled over by the effect of the electric field that on liquid crystal layer 104, produces when when 102,103 of two substrates apply voltage.Known again to have on a side of two substrates 102,103, to form wire projection 115 (not shown) that form the display panels in slit 114 on the opposing party's substrate, this structure makes with the most use in the liquid crystal indicator of current MVA mode.

Patent documentation 1: Japanese kokai publication hei 2-12 communique

Patent documentation 2: No. 4840460 instructions of United States Patent (USP)

Patent documentation 3: No. 3076938 communique of Japan's special permission

Patent documentation 4: TOHKEMY 2002-333870 communique

Figure 24 represents the transmission characteristics and the curve map that applies voltage relationship (T-V characteristic) of the liquid crystal indicator of VA (Vertically Aligned) mode.Transverse axis is represented voltage V that liquid crystal layer is applied, and the longitudinal axis is represented the optical transmission rate.Link among the figure ● the curve A of mark is represented the T-V characteristic on the direction vertical with display frame (hereinafter referred to as " frontal "), the curve B of * mark is represented the T-V characteristic with respect to the direction (hereinafter referred to as " tilted direction ") of display frame 60 ° of 90 °, polar angle at the position angle among the binding figure.Here, the position angle adopts the right with display frame being rotated counterclockwise the angle of calculating on the direction as benchmark.Again, polar angle is the angle that the vertical line erect with the display frame center forms.

As shown in figure 24, near circle C region surrounded, on transmissivity (briliancy) change curve, deform.For example, in applying the lower gray scale of the about 2.5V of voltage, form the transmissivity situation higher of tilted direction, but in the higher gray scale of the ratio that applies the about 4.5V of voltage, form the transmissivity situation lower of tilted direction than the transmissivity of frontal than the transmissivity of frontal.Consequently, the luminance difference effective drive voltage range becomes little under situation about seeing from tilted direction.This phenomenon shows the most significantly on change in color.

Figure 25 A and Figure 25 B represent the variation that can see of the image that shows in the display frame.Figure 25 represents to represent the image seen from tilted direction from image, Figure 25 B that frontal is seen.Shown in Figure 25 A and Figure 25 B, when tilted direction is seen display frame, white partially with the color of when frontal is seen, comparing image.

Figure 26 A～Figure 26 C represents red (R), green (G) of red partially image, blue (B) trichromatic grey level histogram.Figure 26 A represents the grey level histogram of R, and Figure 26 B represents the grey level histogram of G, and Figure 26 C represents the grey level histogram of B.The transverse axis of Figure 26 A～C is represented gray scale (256 gray scales of 0～255), and the longitudinal axis is represented abundance ratio (%).Shown in Figure 26 A～C, in this image, exist with the high abundance ratio than higher gray scale R and lower gray scale G and B.Such image is shown in the display frame of the liquid crystal indicator of VA mode, when tilted direction is seen, the relative deepening of the R of high gray scale, the G and the B of low gray scale brighten relatively.Therefore trichromatic luminance difference becomes little, so become white partially as the picture integral color.

Like this, the liquid crystal indicator of MVA mode or VA mode is at the angle of visibility excellent of frontal.But liquid crystal indicator becomes white partially at picture integral color when tilted direction is seen, has the not enough problem of visual field characteristic.Again, above-mentioned phenomenon takes place in the liquid crystal indicator of TN (Twisted Nematic) mode of the type of drive of the existing model of conduct too.

Summary of the invention

The object of the present invention is to provide a kind of having a wide sphere of vision and the liquid crystal indicator of viewing angle characteristic excellence.

For achieving the above object, liquid crystal indicator of the present invention has the liquid crystal of sealing up for safekeeping between a pair of substrate of subtend configuration; A plurality of pixels in the configuration of a square matrix shape of described subtend substrate; The thin film transistor (TFT) that in described each pixel, forms; To be made up with the low luminance frame that drives described pixel with the briliancy lower to drive the high luminance frame of described pixel than the higher briliancy of regulation briliancy corresponding to the gray-scale value of input image data than the briliancy of described regulation, the briliancy that determines the described pixel in the described high luminance frame is that the briliancy of the described pixel in bright briliancy and the described low luminance frame is dark briliancy, and described high luminance frame and described low luminance frame have a ratio so that obtain the image processing part of the briliancy that equates with described regulation briliancy; The 1st secondary image element that forms in the described pixel; And from separately being formed on the 2nd secondary image element of briliancy of the low briliancy of the per unit area that described the 1st secondary image element in the described pixel obtains with described the 1st secondary image element.

Adopt the present invention, the liquid crystal indicator that then can realize having visual angle broadness and viewing angle characteristic excellence.

Description of drawings

Fig. 1 represents the figure of structure of the liquid crystal indicator of the present invention's the 1st example.

Fig. 2 represents the liquid crystal indicator as the present invention's the 1st example, the figure of the structure of 1 basic pixel of using in capacitive coupling HT method.

Fig. 3 represents the liquid crystal indicator as the present invention's the 1st example, the figure of the cross-section structure of 1 basic pixel of using in capacitive coupling HT method.

Fig. 4 represents the liquid crystal indicator as the present invention's the 1st example, the figure of the equivalent electrical circuit of 1 basic pixel of using in capacitive coupling HT method.

Fig. 5 represents the liquid crystal indicator as the 1st example of the present invention, the figure of the viewing angle characteristic of the VA type liquid crystal indicator of use capacitive coupling HT method.

Fig. 6 A and Fig. 6 B represent the liquid crystal indicator as the present invention's the 1st example, drive HT ratio juris key diagram.

Fig. 7 A and Fig. 7 B represent the liquid crystal indicator as the present invention's the 1st example, drive HT ratio juris key diagram.

Fig. 8 represents as the liquid crystal indicator of the present invention's the 1st example, the graph of a relation between the drive condition that drives the HT method and the flicker generation.

The figure of the setting example of high luminance frame T1 when Fig. 9 A and Fig. 9 B represent as the frequency liquid crystal indicator of the present invention's the 1st example, that 1 group of T is fixed in expression in driving the HT method and the driving frequency of low luminance frame T2.

Figure 10 A and Figure 10 B represent the figure as the visual result of the show state liquid crystal indicator of the present invention's the 1st example, expression driving HT method.

Figure 11 A and Figure 11 B represent as the key diagram liquid crystal indicator of the present invention's the 1st example, that the driving HT method that can improve flicker is described.

Figure 12 A and Figure 12 B represent as the visual valuation result liquid crystal indicator of the present invention's the 1st example, that drive the influence of the pit in the HT method.

Figure 13 represents as the viewing angle characteristic figure liquid crystal indicator of the present invention's the 1st example, when using driving HT method.

Figure 14 represents to use the greyscale transformation table at the liquid crystal indicator of the present invention's the 1st example.

Figure 15 A and Figure 15 B represent the structure of 1 pixel of the liquid crystal indicator of the present invention's the 1st example.

Figure 16 represents the viewing angle characteristic of embodiment 1 of the liquid crystal indicator of the present invention's the 1st example.

Figure 17 represents the viewing angle characteristic of embodiment 2 of the liquid crystal indicator of the present invention's the 1st example.

Figure 18 represents the figure of structure of pixel group PGin of the liquid crystal indicator of the present invention's the 2nd example.

Figure 19 represents the viewing angle characteristic of the liquid crystal indicator of the present invention's the 2nd example.

Figure 20 represents the equivalent circuit diagram of pixel group 39 of the liquid crystal indicator of the present invention's the 3rd example.

Figure 21 represents the viewing angle characteristic of the liquid crystal indicator of the present invention's the 3rd example.

Figure 22 A and Figure 22 B represent the structure of existing vertical orientating type liquid crystal display device.

Figure 23 A～Figure 23 C schematically shows the cross-section structure of the vertical orientating type liquid crystal display device that uses existing orientation cutting techniques.

Figure 24 represents the figure of the T-V characteristic of existing vertical orientating type liquid crystal display device.

Figure 25 A and Figure 25 B represent the variation of the image observation situation that display frame is shown.

Figure 26 A～Figure 26 C represents R, the G of red partially image, the grey level histogram of B.

Label declaration

2,102 TFT substrates

4,103 subtend substrates

6,104 liquid crystal layers

10,11 glass substrates

12,112 grid buss

14,111 drain electrode buses

16,17,109 pixel electrodes

18,117 store capacitance bus

19,116 store capacitance electrode (target)

20、110 TFT

24 contact holes

25 control electrodes

30 dielectric films

32 diaphragms

36,37 alignment films

39 pixel groups

40 CF resin beds

42,118 common electrodes

44a, 44b, 44c, 115 wire projections

46,114 slits

80 grid bus driving circuits

81 image processing parts

82 drain electrode bus driving circuits

83 memory circuits

84 control circuits

86,87,107 polarization plates

88 back light units

101 display panels

105 peripheral encapsulants

106 liners

108 installation terminals

109 vertical alignment layers

120 liquid crystal molecules

Embodiment

The 1st example

Below, the liquid crystal indicator of the present invention's the 1st example is described with Fig. 1～Figure 17.At first, with Fig. 1 the schematic configuration of the liquid crystal indicator of this example is described.Fig. 1 represents the schematic configuration of the liquid crystal indicator of this example.As shown in Figure 1, liquid crystal indicator has TFT substrate 2, and this TFT substrate 2 possesses across grid bus that dielectric film intersects to form mutually and the TFT that drains bus and form on each pixel.This pixel has the 1st and the 2nd secondary image element of cutting apart mutually.Therefore, liquid crystal indicator can use by the illustrated capacity coupled gray scale of partly mixing colours (half-tonegray scale) method (capacitive coupling HT method) of utilizing in back and drive.Again, liquid crystal indicator possesses the subtend substrate 4 that forms CF and common electrode and has for example anisotropic liquid crystal layer of sealing up for safekeeping in 2,4 of two substrates 6 of negative permittivity (not shown) that has.

On TFT substrate 2, be connected and installed with the grid bus driving circuit 80 of the driver IC that drives many grid buss and the drain electrode bus driving circuits 82 that drives the driver IC of many drain drives buses.These driving

circuits

80,82, formation can output to the grid bus of regulation or the structure of drain electrode bus with sweep signal and data-signal according to the signal of the regulation of exporting from control circuit 84.

In the control circuit 84, interior dress is realized partly the mix colours image processing part 81 of gray scale method (drive HT method) of the driving of following explanation.Image processing part 81 needs not to be the circuit of assembling in control circuit 84, also can be another parts that separate with control circuit 84.Also have, image processing part 81 needs not to be concrete circuit, also can be the software of carrying out in the control circuit 84.On the driving circuit 84, connect the memory circuit 83 of storage use at the greyscale transformation table that drives the HT method.Be contained in the memory circuit 83 in the control circuit 84 and also can.

Form on the face of the opposite side of face with the TFT element of TFT substrate 2, configuration polarization plates 87, form on the face of opposition side of face configuration polarization plates 87 and intersecting Nicol prism (Japanese: Network ロスニコ Le) go up the polarization plates 86 of configuration at the common electrode of subtend substrate 4.Opposing configuration back light unit 88 on the face of a side with the TFT substrate 2 of polarization plates 87.

Then, with Fig. 2～Fig. 5 capacitive coupling HT method is described.Capacitive coupling HT method is to improve the technology of above-mentioned viewing angle characteristic.In patent documentation 1～3, publicity the capacitive coupling HT method in the liquid crystal indicator of TF mode.Fig. 2 represents the structure according to 1 pixel of the basic liquid crystal indicator of these known technologies, and Fig. 3 is illustrated in the cross-section structure of the liquid crystal indicator that the X-X line of Fig. 2 cuts off, and Fig. 4 represents the equivalent electrical circuit of 1 pixel of this liquid crystal indicator.As Fig. 2～shown in Figure 4, the liquid crystal layer 6 that liquid crystal indicator has thin film transistor (TFT) (TFT) substrate 2 and subtend substrate 4 and is sealed in 2,4 of two substrates.

TFT substrate 2 has many grid buss 12 that form on the glass substrate 10 and many drain electrode buses 14 that intersect to form across dielectric film 30 on grid bus 12.Near the crossover location of grid bus 12 and drain electrode bus 14, the TFT20 that configuration forms on each pixel as on-off element.The part of grid bus 12 works as the gate electrode of TFT20, and the drain electrode of TFT20 (D) is electrically connected in drain electrode bus 14.Again, the pixel region that crosscut delimited by grid bus 12 and drain electrode bus 14 forms the storage capacitance bus 18 that prolongs side by side with grid bus 12.On each pixel, form storage capacitance electrode (target) 19 across dielectric film 30 on the storage capacity bus 18.Store capacitance electrode 19 and be electrically connected source electrode (S) at TFT20 by control electrode 25.Utilize the dielectric film 30 of storing capacitance bus 18, storage capacitance electrode 19 and being clipped between them to form storage capacitor C s.

The pixel region that utilizes grid bus 12 and drain electrode bus 14 to delimit is split into secondary image element (the 1st secondary image element) A and secondary image element (the 2nd secondary image element) B.In the plain A of secondary image, form pixel electrode (the 1st pixel electrode) 16, in the plain B of secondary image, form the pixel electrode (the 2nd pixel electrode) 17 that separates with pixel electrode 16.Pixel electrode 16 is electrically connected at the source electrode (S) of storing capacitance electrode 19 and TFT20 by contact hole 24.Pixel electrode 17 has across diaphragm 32 overlapping areas on control electrode 25.In this zone, utilize pixel electrode 17, control electrode 25 and the diaphragm 32 in being clipped in two

electrodes

17,25, form control capacitance Cc.The capacitive coupling that pixel electrode 17 utilizes by control capacitance Cc is connected source electrode (S) indirectly.Pixel electrode 17 forms electric unsteady state.

Subtend substrate 4 has the common electrode 42 in color filter (CF) resin bed 40 that forms on the glass substrate 11 and formation on CF resin bed

40.Pixel electrode

16 and 42 of common electrodes at the plain A of secondary image form liquid crystal capacitance C1c1, at

pixel electrode

17 and 42 formation of the common electrode liquid crystal capacitance C1c2 of the plain B of secondary image.Liquid crystal capacitance C1c2 and control capacitance Cc are connected in

series

2,4 of two substrates.On the interface of TFT substrate 2 and the liquid crystal layer 6 of subtend substrate 4,

form alignment films

36,37 respectively.

TFT20 is when conducting state, and the grayscale voltage (corresponding to the voltage of the gray-scale value of input image data) that is applied to drain electrode bus 14 is applied to pixel electrode 16 by TFT20, applies voltage Vpx1 on the liquid crystal layer 6 of the plain A of secondary image.Therefore at this moment, cut apart voltage Vpx1, on the pixel electrode 17 of the plain B of secondary image, applied the voltage different with pixel electrode 16 according to the capacity ratio of liquid crystal capacitance C1c2 and control capacitance Cc.The voltage Vpx2 that applies on the liquid crystal layer 6 of sub-pixel electrode B is as follows:

Vpx2＝(Cc/(C1c2+Cc))×Vpx1…(1)

Actual voltage ratio, (Vpx2/Vpx1 (=Cc/ (C1c2+Cc))) is the design item based on the display characteristic of liquid crystal indicator, if but adopt 0.6～0.8th, desirable.

Like this, to being applied to the grayscale voltage of drain electrode bus 14, if different mutually secondary image plain A, the B of the voltage that the liquid crystal molecule of liquid crystal layer 6 begins to tilt (threshold voltage) exists in per 1 pixel, then T-V characteristic distortion is as shown in figure 24 disperseed by secondary image plain A, B.Therefore, adopt capacitive coupling HT method, can be suppressed at the phenomenon that image became white when tilted direction is seen, can improve viewing angle characteristic.As long as capacitive coupling HT method makes the threshold voltage diverse ways be not limited to capacitive coupling plain at the different mutually secondary image of threshold voltage at 1 pixel internal storage.For example, also can on pixel electrode, form dielectric, or change the orientation of liquid crystal molecule and make it stretch (uncurling), make the threshold voltage difference.

Fig. 5 represents to use the curve map of viewing angle characteristic of the VA type liquid crystal indicator of capacitive coupling HT method.The gray scale of transverse axis display image data, the longitudinal axis are represented the γ value.Here, with the maximum briliancy from the optical characteristics of the direction detection of the angle that becomes regulation with the normal direction of display frame is T, from being ta with the equidirectional briliancy of the angle of this regulation, being tb based on the briliancy of gray-scale value b (a and b are different values) based on gray-scale value a, when the ratio of briliancy ta and briliancy b and maximum briliancy T is respectively Ta and Tb, the calculating as described below of γ value.

γ＝{log(Ta)-log(Tb)}/{log(a)-log(b)}…(2)

Link among the figure ● the characteristic on the frontal of the liquid crystal indicator of the curve representation use capacitive coupling HT method of mark, to make the area ratio of plain A of secondary image and the plain B of secondary image be 1: 9 to the curve representation of mark among the binding figure, is designed to voltage ratio Vpx2/Vpx1 in the middle gray (127/255 gray scale) and is the characteristic of the tilted direction of 0.72 liquid crystal indicator.To make the area ratio of plain A of secondary image and the plain B of secondary image be 2: 8 to the curve representation of △ mark among the binding figure, be designed to voltage ratio Vpx2/Vpx1 in the middle gray (127/255 gray scale) and be the characteristic of the tilted direction of 0.67 liquid crystal indicator, link among the figure * to make the area ratio of plain A of secondary image and the plain B of secondary image be 4: 6 to the curve representation of mark, is designed to voltage ratio Vpx2/Vpx1 in the middle gray (127/255 gray scale) and is the characteristic of the tilted direction of 0.67 liquid crystal indicator.Dotted line shown in the figure is represented the characteristic of the tilted direction of existing VA type liquid crystal indicator.

Among Fig. 5, be set at for γ value at the viewing angle characteristic of tilted direction under 2.4 the condition and measure the local γ value of each gray scale frontal.As the formula (2), the difference of briliancy ta, tb that corresponds respectively to 2 gray-scale values is big more, and then the γ value becomes big more.Thereby,, then just reduce by the diminish change in color of the display frame that produces of the difference that makes this briliancy if can make the γ value of tilted direction become relatively large.The viewing angle characteristic of liquid crystal indicator γ value in whole gray scales (0～255 gray scale) is all 2.4 mutually with the front, is desirable.Shown in the dotted line among the figure, in the existing liquid crystal indicator that does not use capacitive coupling HT method, the γ value drops to below 1 in the scope of the ratio broad of 0～192 gray scale, and the viewing angle characteristic of tilted direction is insufficient.

On the other hand, as link respectively among the figure mark, △ mark and * curve of mark shown in, use the liquid crystal indicator of capacitive coupling HT method to improve viewing angle characteristic greatly, in the scope of 0～224 gray scale, the maximal value of γ value forms more than 1.5.But for improving viewing angle characteristic, it is more satisfactory making the γ value more approach 2.4.Under the image situation relatively of the image of γ=2.4 and γ=1.5, the show state of two images does not have big difference.Therefore, the desired value of among the application viewing angle characteristic being improved is set at γ 〉=1.5.

As shown in Figure 5, in the capacitive coupling HT method, the tonal range of improving viewing angle characteristic is different with the area ratio of the plain B of secondary image because of the plain A of secondary image.When the area of the plain B of the secondary image that utilizes capacitive coupling to drive diminished, the gray-scale value that improves viewing angle characteristic became big.Therefore, for example show blackly when sending out relative low image gray more, be varied down to optimumly by the area that makes secondary image element B, can seek to improve the viewing angle characteristic of liquid crystal indicator with meat etc.Again, for example, when the relative like that high image gray of the clothes of muscle that shows the people and white, become greater to optimumly by the area ratio that makes secondary image element B, can seek to improve the viewing angle characteristic of liquid crystal indicator.

The tonal range of improving viewing angle characteristic is the narrow scope about 30～40 gray scales.Therefore, even use capacitive coupling HT method, seek in that stable to improve viewing angle characteristic also be difficult than the tonal range of broad.

As other the method for improving viewing angle characteristic, known have the HT of a driving method.Describe driving the HT method with Fig. 6 A～Figure 13 below.Drive the HT method for being made up with the low luminance frame that drives pixel with the briliancy lower to drive the high gray scale frame of pixel than the higher briliancy of regulation briliancy corresponding to the gray-scale value of input image data than the briliancy of described regulation, determine the ratio that exists of the briliancy (hereinafter referred to as " bright briliancy ") of the pixel in the described high luminance frame and the briliancy of the pixel in the described low luminance frame (hereinafter referred to as " dark briliancy ") and described high luminance frame and described low luminance frame, with the image processing method of the briliancy that obtains equating in fact with the regulation briliancy.Here, so-called regulation gray scale is meant and does not use the briliancy that obtains when driving the HT method.

Fig. 6 A～Fig. 7 B drives HT ratio juris key diagram.Fig. 6 A and Fig. 7 A represent the ratio that exists of high luminance frame and low luminance frame.Transverse axis express time among the figure, the longitudinal axis is represented the briliancy in each frame.Fig. 6 B schematically shows to use and drives the display frame that the HT method drives.In some pixels, be provided with make its than with the brighter high luminance frame T1 of the corresponding regulation briliancy of the gray-scale value of input image data A briliancy with make it than its darker low luminance frame T2.Being bright briliancy B (bright briliancy B＞briliancy A) in high luminance frame T1, is dark briliancy C (dark briliancy C＜briliancy A) in low luminance frame T2.Bright briliancy B and dark briliancy C set to such an extent that make the briliancy A of average luminance that the combination of high luminance frame T1 and low luminance frame T2 obtains and regulation identical.

The example that exists ratio to realize in time of representing to make high luminance frame T1 and low luminance frame T2 at Fig. 6 A and Fig. 6 B with 1: 3 ratio.As shown in Figure 6A, to 1 high luminance frame T1, low luminance frame T2 is arranged continuously 3 times then.This 1 high luminance frame T1 and 3 low luminance frame T2 as 1 group of T, are repeated this group T as time series.For example, when driving whole display frame with this condition, shown in Fig. 6 B, the display frame t1 that drives with high luminance frame T1 mixes on time-axis direction with the display frame t2 that drives with low luminance frame T2, equalization forms the display frame t it seems with the consistent in fact briliancy of regulation briliancy A.

The example that exists ratio to realize in time of representing to make high luminance frame T1 and low luminance frame T2 at Fig. 7 A and Fig. 7 B with 1: 1 ratio.In the present example, 1 high luminance frame T1 and 1 low luminance frame T2 as 1 group of T, are repeated this group T as time series.For example, when driving the demonstration whole image with this condition, shown in Fig. 7 B, the display frame t1 that drives with high luminance frame T1 mixes on time-axis direction with the display frame t2 that drives with low luminance frame T2, equalization, and the display frame t with the consistent in fact briliancy of regulation briliancy A is it seems in formation.

Drive the HT method if adopt, then can reduce the demonstration frequency of the middle gray of viewing angle characteristic difference, improve viewing angle characteristic on the whole.In this case, shown in Fig. 6 B and Fig. 7 B, be whole pixels during simultaneously for the state of bright briliancy or dark briliancy (light and shade) making whole image, in whole image, see flicker.

The frame that Fig. 8 represents to change high luminance frame T1 and low luminance frame T2 than (T1: T2) and the flicker under the situation of the driving frequency of 1 group of T whether take place.Among the figure zero and * represent respectively unidentifiedly to go out flicker and identify flicker.As mentioned above, make whole image become the frame of bright briliancy to show repeatedly, when making it that light and shade luminance difference be arranged, experience flicker in people's the eyes with making its frame that becomes dark briliancy.This flicker can relax by improving frequency.Particularly, the known flicker component that makes is just can not discern more than or equal to 60Hz.

Thereby, as shown in Figure 8, make frame than (T1: T2) be 1: 1, improve the driving frequency of 1 group of T, be 2 times the 120Hz of driving frequency (60Hz) of 1 frame of common liquid crystal indicator.So, the frequency that shows high luminance frame T1 be 60Hz (=120Hz/2).Therefore be difficult to find out flicker.But, when frame than (T1: when T2) being 1: 2, for example, when the driving frequency of 1 group of T is 120Hz, the frequency that shows high luminance frame T1 be 40Hz (=120Hz/3),, therefore can not suppress flicker fully because frequency reduces in fact.

Equally, when frame than (T1: when T2) being 1: 3, for example, when the driving frequency of 1 group of T is 120Hz, the frequency that shows high luminance frame T1 be 30Hz (=120Hz/4), can not fully suppress the flicker.It is poor to be provided with during the demonstration of high luminance frame T1 and low luminance frame T2, just must be with high more frequency drives.Though also be related to the resolution of display frame, if but the driving frequency of 1 group of T is decided to be more than 3 times of driving frequency of 1 frame of liquid crystal indicator, then the burden of peripheral driving circuit (control circuit 84, gate drivers IC and source electrode driver IC) becomes big, and it realizes very difficulty.

As the countermeasure of this problem, the driving frequency of fixing 1 group of T is arranged, change the method for the driving frequency of each frame T1, T2 respectively.The setting example of each driving frequency of each frame T 1, T2 when Fig. 9 A and Fig. 9 B represent that the driving frequency with 1 group of T is fixed as 120Hz.Fig. 9 A represents that frame is than (T1: T2) be 1: 1 setting example, Fig. 9 B represents that frame is than (T1: T2) be 1: 3 setting example.Transverse axis express time among the figure, the longitudinal axis is represented briliancy.

Shown in Fig. 9 A and Fig. 9 B, when the driving frequency of 1 group of T was fixed as 120Hz, even change each driving frequency of each frame T1, T2, the frequency that shows high luminance frame T1 or low luminance frame T2 also was that 60Hz is constant.Therefore the flicker that can suppress to take place in the display frame.

The visual result who represents the show state of this driving HT method as Figure 10 A and Figure 10 B.Figure 10 A represents to have the visual result of flicker free generation.Figure 10 B represents the visual result who improves effect of viewing angle characteristic.Figure 10 A zero or * expression respectively the expression do not see flicker (zero) and see flicker (*).Figure 10 B zero, △ or * expression has improved viewing angle characteristic (zero), no problem in improvement, the practicality (△) arranged, has not improved (*) respectively.As shown in figure 10, more than the driving frequency stuck-at-20Hz with 1 group of T, the display frequency of high luminance frame T1 or low luminance frame T2 becomes more than the 60Hz.Therefore, at frame than (T1: T2) be in 1: 1,1: 2 or 1: 3 any one, flicker does not worsen.

And when the driving frequency of 1 group of T uprised (frame during shorten), response speed of liquid crystal was not followed this drive frequency variations, and shown in Figure 10 B, the effect of improving of viewing angle characteristic is progressively lost.If make the response speed of liquid crystal high speed in the future, also can improve gray scale briliancy characteristic even driving frequency is uprised.But even will make the response speed of liquid crystal high speed, frame is than (T1: T2) approach also surely to prevent flicker generation and easily improve viewing angle characteristic at 1: 1.

Under the situation of present liquid crystal response speed, can prevent the generation of glimmering, and be that any one all is zero among Figure 10 A and the B for obtaining the only condition that viewing angle characteristic improves effect, frame is than (T1: T2) be 1: 1, the frequency of 1 group of T is the such condition of 120Hz.

Figure 11 A and Figure 11 B are in order to illustrate the driving HT method that can suppress to glimmer, schematically show the determined pixel group of the viewing area of liquid crystal indicator, specifically, 16 rectangular pixels of 4 * 4 are treated as a unit, the example of the light and shade of each pixel is set in expression.Among Figure 11 A, with the light and shade of 16 pixels in each frame, the end limit is cut apart with 1: 3 ratio non-conterminously between the high luminance pixel, and with the light and shade of 16 pixels in each frame, the end limit is cut apart with 1: 1 ratio non-conterminously between the high luminance pixel in Figure 11 B.Also have, the frame number of every regulation is made the light and shade change of each pixel.For example, the light and shade of every frame is set at for the cycle variation of each pixel with 1: 3 in Figure 11 A.For example, when visual pixel P, pixel P changes with bright-dark-dark-Ming from the 1st frame to the 4 frames.

In Figure 11 B, the light and shade of every frame is set at the cycle variation of each pixel with 1: 1.For example when visual pixel P, pixel P from the 1st frame to the 4 frames with bright-dark-Ming-dark variation.Like this, pattern according to the rules by disperseing the light and shade in the viewing area, can realize not seeing the demonstration of flicker.

When Figure 12 A and Figure 12 B are illustrated in the driving HT method of using shown in Figure 11 A and Figure 12 B, the impact assessment result of the pit that takes place in the visual valuation display frame.Figure 12 A represents to have the visual result of the liquid crystal indicator of the pixel that pel spacing is configured to 0.03mm.Figure 12 B represents to have the visual result of the liquid crystal indicator of the pixel that pel spacing is configured to 0.45mm.There is ratio in " HT is cut apart the light and shade ratio " shown in Figure 12 A and Figure 12 B bright briliancy of expression and dark briliancy in display frame.Again, the driving frequency of 1 group of T is 60Hz.The ◎ of Figure 12 A and Figure 12 B, zero or * respectively expression do not feel fully pit (◎), feel some pits but practical no problem (zero), feel unhappy sensation (*) is arranged pit.

As still frame shows, show at certain hour under the situation of identical video, owing to making the briliancy equalization make pit not become problem.But, drive in the HT method since moment bright pixel and dark pixel mix, therefore under animation display is painted the situation of motion like that and under the situation of viewpoint motion, the user has felt pit.Shown in Figure 12 A and Figure 12 B, when the pixel ratio of the dark briliancy in the viewing area becomes big, feel pit easily.Also has the near more easy more pit of feeling of the distance of user and display frame.In the light and shade cycle (cycle of 1 group of T) is when the user is near liquid crystal indicator under the situation of 60Hz, and the ratio that exists of the bright briliancy in 1 picture and dark briliancy is beyond 1: 1 the time, feels that offensively the possibility of pit uprises.In driving the HT method, what also might make interior bright briliancy of 1 picture and dark briliancy exists ratio beyond 1: 1, but in order to obtain superior display quality, preferably the ratio that exists with light and shade is set at 1: 1.

As mentioned above, viewing angle characteristic is improved, guarantee the good display quality of not flicker and pit, the condition of the optimal driving HT method that interpolation is not loaded to peripheral driving circuit is as described below.

The frame of high luminance frame and low luminance frame is than (T1: T2) be 1: 1, the bright briliancy in 1 pixel is 1: 1 with the ratio that exists of dark briliancy, and driving frequency is 60Hz.Below this condition is called the top condition that drives HT.

Figure 13 represents to drive the curve of the viewing angle characteristic of the VA type liquid crystal indicator under the HT top condition.Transverse axis is represented the gray scale of display image data, represents the γ value in a word.Link among the figure ◆ the characteristic on the frontal of the liquid crystal indicator of the curve representation use driving HT method of mark, the curve representation that links the △ mark among the figure uses the characteristic of the tilted direction of the liquid crystal indicator that drives the HT method, the characteristic of the tilted direction of the existing VA type of the curve representation among the figure shown in dotted line liquid crystal indicator.In Figure 13, the viewing angle characteristic of tilted direction is set in the γ value with frontal on 2.4 the basis and measures, and is the γ value of the locality in each gray scale.

As shown in figure 13, when use driving the HT top condition, therefrom can improve viewing angle characteristic to high gray scale (from about 130 gray scales to 255 gray scales).But, drive in the HT top condition, in the image of low gray scale side (below about 100 gray scales), almost can not get the effect of improving of viewing angle characteristic.When frame than (T1: be beyond 1: 1 the time T2), generation can improve the viewing angle characteristic of low gray scale side, but flicker and pit are arranged.Like this, under only with the situation that drives the HT method, in the high-gray level scope, viewing angle characteristic improve effect and good display quality is difficult to realize simultaneously.

Therefore, in the liquid crystal indicator of this example, by capacitive coupling HT method combine with the driving liquid crystal indicator with driving the HT method, seek viewing angle characteristic improve effect and good display quality is realized simultaneously.Because the restriction of liquid crystal response speed and peripheral driving circuit has limited the drive condition that drives the HT method.Therefore, decision drives the drive condition of HT method in this example, with the optimization of its combination realization capacitive coupling HT method.

Below, use embodiment to be specifically described.

Embodiment 1

The liquid crystal indicator of present embodiment is suitable in the drive condition that drives the HT method and drives the HT top condition.Figure 14 represents to possess the high briliancy side gray-scale value that the bright briliancy that obtains in the high gray scale frame uses and obtains the greyscale transformation table of the low gray scale side gray-scale value that the dark briliancy in the low luminance frame uses.Transverse axis is represented input gray level.The longitudinal axis in left side is represented output gray level (gray scale after the conversion), and the longitudinal axis on right side is with the normalized briliancy of maximum briliancy.Link among the figure ◆ the curve A of mark is represented low briliancy side gray scale, and the curve B that links the ■ mark is represented high briliancy side gray-scale value.The curve C of binding * mark is represented common briliancy (regulation briliancy) among the figure, and the curve D that links zero mark among the figure is represented by the briliancy (HT handles the back briliancy) that drives after the HT method is carried out Flame Image Process.

As shown in figure 14, for example, be under the situation of 128/255 gray scale at input gray level, low luminance frame is transformed to 10/255 gray scale from curve A, and high luminance frame is transformed to 245/255 gray scale from curve B.The ratio of each image duration is 1: 1, and in fact the briliancy after the conversion that shows in the liquid crystal indicator is the synthetic briliancy of this two frame, obtains about 38% briliancy (curve D) of maximum briliancy.Usually briliancy (curve C) is handled back briliancy (curve D) with HT and is almost demonstrated identical characteristic, even understand thus and carry out this conversion, positive briliancy is also kept the briliancy of the image that does not use driving HT method.This greyscale transformation table only is an example.The restriction item of greyscale transformation is just constant in the positive briliancy in greyscale transformation front and back, if satisfy this restriction item, also can be the greyscale transformation table beyond this greyscale transformation table.

Form the greyscale transformation table and be stored in the memory circuit 83 (with reference to Fig. 1), when liquid crystal indicator energized for example, can be read into the such structure of RAM (not shown) in the image processing part 81.

Figure 15 A and Figure 15 B represent the structure of 1 pixel of the liquid crystal indicator of present embodiment.Figure 15 A is illustrated in normal direction and sees glass substrate 10, forms the structure of 1 pixel in rectangular a plurality of pixels.Figure 15 B represents the section with the cut-out of the X-X line shown in Figure 15 A.Shown in Figure 15 A and Figure 15 B, forming many grid buss 12 on the glass substrate 10, intersecting at many drain electrode buses 14 that form on the grid bus 12 across dielectric film 30.Grid bus 12 and the drain electrode bus 14 crossover location near, dispose the TFT20 that forms on each pixel.The part of grid bus 12 works as the gate electrode (G) of TFT20.On grid bus 12, form work semiconductor layer and the channel guard film (not illustrating) of TFT20 across dielectric film.At gate electrode (G), be on the channel guard film of TFT20, form drain electrode (ID) and the n type impurity semiconductor layer (not illustrating) of lower floor and the n type impurity semiconductor layer (not illustrating) of source electrode (S) and lower floor thereof across the specified gap subtend.

Again, the pixel region that crosscut delimited by grid bus 12 and drain electrode bus 14 forms the storage capacitance bus 18 that extends side by side with grid bus 12.On each pixel, forming storage capacitance electrode (target) 19 across dielectric film on the storage capacity bus 18.Store capacitance electrode 19 and be electrically connected source electrode (S) at TFT20 by control electrode 25.The dielectric film 30 formation storage capacitor C s that utilize and store capacitance bus 18, store capacitance electrode 19 and between them, clip.

The pixel region of being delimited by grid bus 12 and drain electrode bus 14 is divided into secondary image element (the 1st secondary image element) A and secondary image element (the 2nd secondary image element) B.The area of the plain A of secondary image and the plain B of secondary image is than (A: B) be 3: 7.For example, the central portion that the plain A of trapezoidal secondary image the is disposed at pixel region side that keeps left, the plain B of secondary image is disposed at extra-regional top, bottom and the central portion right-hand end except that the plain A of the secondary image in the pixel region.The configuration of secondary image in the pixel region plain A, B almost becomes rotational symmetry with respect to storing capacitance bus 18.On the plain A of secondary image, form pixel electrode (the 1st pixel electrode) 16.On the plain B of secondary image, form and separate the pixel electrode (the 2nd pixel electrode) 17 that separates in slit 46 with pixel electrode 16.Pixel electrode 16,17 and all forming with nesa coatings such as ITO.Pixel electrode 16 is electrically connected on the source electrode (S) of storing capacitance electrode 19 and TFT20 by the contact hole 24 that makes diaphragm 32 openings.Pixel electrode 17 has across diaphragm 32 and control electrode 25 overlapping areas.In this zone, utilize control electrode 25, pixel electrode 17 to reach and form control capacitance (regulation electric capacity) Cc at 17,25 diaphragms that clip of two electrodes 32.Pixel electrode 17 forms electric quick condition.

On the subtend glass substrate 11 of subtend configuration on the glass substrate 10, form CF resin bed 40 and common electrode 42 in order.Outstanding, on the position of control electrode 25 subtends of oblique extension among Figure 15 A, form as the orientation limitations in the orientation orientation of the liquid crystal molecule of restriction liquid crystal layer 6 wire projection 44a with member from subtend glass substrate 11.Again, becoming in fact on the axisymmetric position, from the subtend glass substrate 11 outstanding wire projection 44b that form with respect to storing capacitance bus 18.Also have, the central portion of the pixel region side that keeps left forms the wire projection 44c that is disposed at the V word shape on the pixel electrode 16.Wire projection 44c forms rotational symmetry in fact with respect to storing capacitance bus 18.

On the plain A of secondary image, utilize pixel electrode 16, common electrode 42 and form liquid crystal capacitance C1c1 at 16,42 liquid crystal layers that clip of two electrodes 6.The liquid crystal layer 6 that utilizes pixel electrode 17, common electrode 42 and clip between two electrodes on the plain B of secondary image forms liquid crystal capacitance C1c2.11 of glass substrate 10 and subtend glass substrates, liquid crystal capacitance C1c2 and control capacitance Cc are connected in series.

The voltage Vpx2 that applies on the liquid crystal capacitance C1c2 of the plain B of secondary image under the situation of TFT20 one-tenth conducting state utilizes above-mentioned formula (1) to try to achieve.In the present embodiment, to be designed to Vpx2/Vpx1 be 0.27 in middle gray (127 gray scale) to the voltage ratio of the voltage Vpx2 that applies on the liquid crystal capacitance C1c2 of the voltage Vpx1 that applies on the liquid crystal capacitance C1c1 of the plain A of secondary image and secondary image element B.

Be applied to the grayscale voltage (gray-scale value of corresponding input image data or the voltage of the gray-scale value after the greyscale transformation) that applies on the drain electrode bus 14 on the liquid crystal capacitance C1c1 of the plain A of secondary image.Therefore, in the plain A of secondary image, obtain with high luminance frame in bright briliancy or the almost equal briliancy of dark briliancy in the low luminance frame.On the liquid crystal capacitance C1c2 of the plain B of secondary image, apply such as the low low-voltage of grayscale voltage that is applied to drain electrode bus 14 shown in the formula (1) again.Therefore, in the plain B of secondary image, obtain briliancy than bright briliancy in the high luminance frame or the lower briliancy of dark briliancy in the low luminance frame.

Figure 16 represents the curve map of the viewing angle characteristic of VA type liquid crystal indicator.Transverse axis indicates the gray scale of view data, and the longitudinal axis indicates the γ value.Link among the figure ◆ the characteristic on the frontal of the liquid crystal indicator of the curve representation present embodiment of mark.The curve representation of binding ▲ mark does not use the characteristic of the tilted direction when driving the HT method only with capacitive coupling HT method driving liquid crystal indicator among the figure, the characteristic of the tilted direction the when curve representation that links the ■ mark among the figure drives existing VA liquid crystal indicator with best HT drive condition, the characteristic of tilted direction of liquid crystal indicator that links the curve representation present embodiment of zero mark among the figure, the curve representation among the figure shown in the dotted line are not used the characteristic of capacitive coupling HT method and the tilted direction of the existing VA type liquid crystal indicator that drives the HT method.Among Figure 16, each viewing angle characteristic of tilted direction is measured the γ value of the part of each gray scale then for the γ value of the frontal more than 96 gray scales is set 2.4.

As shown in figure 16, in the existing VA type liquid crystal indicator shown in the dotted line, the γ value is below 1.0 in most of gray areas (about 200 gray scales are following).Therefore, the vividness of image has just been lost.To this, only use peak value that its characteristic of characteristic (▲ mark) of tilted direction of the liquid crystal indicator of capacitive coupling HT method improves near 110/255 gray scale, the γ value is more than 1.5 in the subrange about 100～120 gray scales.Also have, even γ value is about 1.0 also in the tonal range beyond these, viewing angle characteristic is improved.

The characteristic (■ mark) of the tilted direction when driving existing VA type liquid crystal indicator with best HT drive condition has the γ value about 1.5 more than 140/255 gray scale, improve to high gray scale one side characteristic in gray scale therefrom.But, the low gray scale side below 128/255 gray scale, the γ value is about 1.0.The characteristic (zero mark) of the liquid crystal indicator when capacitive coupling HT method is driven with the combination of driving HT method can confirm that in 64/255～192/255 extremely wide tonal range the γ value surpasses 1.5.Improving characteristic like this, is because capacitive coupling HT method is mainly improved low gray areas, and the HT method is mainly improved therefrom gray scale to high gray areas, and what consequently make two kinds of HT methods improves the effect addition.Like this, liquid crystal indicator is obtaining the effect that viewing angle characteristic improves in the gray areas widely.In case obtain high γ characteristic in gray areas widely, can both improve viewing angle characteristic for any image, therefore can access liquid crystal indicator with extremely good display characteristic.

In 1 pixel, changes the capacitive coupling HT method of threshold voltage and made up by forming secondary image plain A, B, make viewing angle characteristic well be improved effect with driving HT method in high briliancy and low luminance frame driving pixel.By being made up, HT technology different on the principle makes that both improve the effect addition.As mentioned above, restriction is arranged on drive condition, in high gray scale, obtain the good effect of improving in gray scale therefrom, but improve relatively more difficult in low gray scale side owing to drive the HT method.And make the different capacitive coupling HT technology of threshold voltage improve any gray scale in proper order with the setting of the ratio of the area of secondary image plain A, B and the voltage ratio Vpx2/Vpx1 of the liquid crystal capacitance C1c1, the C1c2 that are applied to the last formation of plain A, the B of two secondary images.But in capacitive coupling HT method, it is difficult equally improving characteristic in broad gray areas.

Therefore adopt to utilize to drive the HT method and improve therefrom gray scale, utilize the such different HT technology of threshold voltage that in 1 pixel, makes of capacitive coupling HT method to improve design from low gray scale to high gray scale one side to high gray scale one side.Like this, consequently can in the broader region of high gray scale, improve viewing angle characteristic from low gray scale.That does not repeat two kinds of HT methods improves effect ground, in the scope below 220 gray scales for example (in the scope of the regulation of gray-scale value), make when only driving pixel with capacitive coupling HT method, the γ value is maximum 110/255 gray scale (gray-scale value α) with when driving the HT method and only drive the pixel (pixel of existing MVA type liquid crystal indicator) that is formed by the plain A of secondary image, and the γ value is 200/255 gray scale (gray-scale value β) inconsistent (gray-scale value α＜gray-scale value β) of maximum.

As mentioned above, most suitably made up with driving HT technology by the HT technology that will in 1 such pixel of capacitive couplings, be provided with threshold voltage difference, can access and only use each HT technology unavailable, in wide tonal range, have the liquid crystal indicator of good viewing angle characteristic.By driving the drive condition optimization of HT method, can access the liquid crystal indicator that excellent display quality is arranged that in display frame, does not have flicker and pit again.

Embodiment 2

The structure of the liquid crystal indicator of present embodiment, except the area ratio of plain A of secondary image and the plain B of secondary image was 4: 6 this point, other liquid crystal indicators with the foregoing description were identical.

Figure 17 represents the curve map of the viewing angle characteristic of VA type liquid crystal indicator.The gray scale of transverse axis presentation video data, the longitudinal axis is represented the γ value.Link among the figure ◆ the characteristic on the frontal of the liquid crystal indicator of the curve representation present embodiment of mark.The characteristic of the tilted direction the when characteristic of the tilted direction the when curve representation of binding ▲ mark does not use and drives the HT method and only drive liquid crystal indicator with capacitive coupling HT method among the figure, the curve representation that links the ■ mark among the figure drive existing VA liquid crystal indicator with optimal HT drive condition.The characteristic of tilted direction of liquid crystal indicator that links the curve representation present embodiment of zero mark among the figure, the curve representation among the figure shown in the dotted line are not used the characteristic of capacitive coupling HT method and the tilted direction of the existing VA type liquid crystal indicator that drives the HT method.Among Figure 17, each viewing angle characteristic of tilted direction is measured the γ value of the part of each gray scale again for the γ value of the frontal more than 96 gray scales is set 2.4.

In the present embodiment, the area ratio of plain A, B of secondary image is different from the foregoing description 1.Therefore, as shown in figure 17, only use the characteristic (▲ mark) of tilted direction of the liquid crystal indicator of capacitive coupling HT method, the peak value that its characteristic is improved is near 140/255 gray scale, and γ is more than 1.5 in the subrange about 128～150 gray scales.Also have, also about 1.0, viewing angle characteristic is improved the γ value in tonal range in addition.Again, in the present embodiment, owing to changed the drive condition that drives the HT method, therefore only the characteristic (■ mark) of the tilted direction of the existing VA type liquid crystal indicator of use driving HT method is identical with the foregoing description 1.

Can confirm with capacitive coupling HT method with drive characteristic (zero mark) that the HT method made up the liquid crystal indicator when driving in the extremely wide tonal range of 96/255 gray scale～192/255 gray scale γ value above 1.5.But different with the viewing angle characteristic of the foregoing description 1, low gray scale side (96 gray scales below) improve some minimizing of effect, on the other hand, near the γ value of 128/255 gray scale is 1.8, it is higher to improve effect.This be because, utilize gray areas in the improvement of capacitive coupling HT method, utilize driving the HT method improves therefrom gray scale and utilizes the addition that improves effect of two kinds of HT methods, the effect of the viewing angle characteristic that improves to the zone of high gray scale in the vast zone that particularly with middle gray scale is the center.

Like this,, compare with the foregoing description 1 if adopt this example, poor slightly for the dark image display feature of low gray scale side, but the image of intermediate gray-scale side obtains suitable demonstration.As the more image of moderate gray scale, if different with the actual color of muscle of people etc. then image that the people is felt very ill is a lot, the viewing angle characteristic of present embodiment is more better than this characteristic of the foregoing description 1 sometimes.

As mentioned above, if use the liquid crystal indicator of present embodiment,, can only be used each HT method unavailable, the good viewing angle characteristic in vast tonal range by suitably capacitive coupling HT method being made up with driving the HT method.Particularly adopt the liquid crystal indicator of present embodiment, can utilize gray areas in the improvement of capacitively coupled HT method, utilize to drive the HT method and improve therefrom gray scale to the zone of high gray scale, by means of this, if can be different with the actual color of muscle of people etc. then moderate gray scale that image that the people is felt very ill uses a lot obtains big viewing angle characteristic improves effect.

Shown in above-mentioned embodiment 1 and embodiment 2, not only capacitively coupled HT method and driving HT method are made up merely, also will be as the improvement zone of appropriate combination two HT methods, set the area ratio of secondary image plain A, B and voltage ratio Vpx1, the Vpx2 of the liquid crystal capacitance C1c1, the C1c2 that are applied to secondary image plain A, B, this also is important.Particularly utilize to drive the HT method improve from low gray scale to gray scale, be difficult at present fastening with the pass of liquid crystal response speed etc.Therefore, the capacitively coupled HT method of otherwise combined, can to from low gray scale to the improvement of the gray scale condition of carrying out interpolation be suitable.For example as the condition of capacitively coupled HT method, when the area of secondary image plain A, B than surpassing A: B=5: the effect of improving of low gray scale side diminishes in the time of 5, is unaccommodated therefore.

But, use to drive the HT method from low gray scale to the gray scale effect that improves be not impossible.As the demonstration of public place, in the purposes of the distance from display frame to user, use under the situation of liquid crystal indicator, shown in Figure 12 A and Figure 12 B, purpose is out of question.Again, if with frame rate during from current general frequency 60Hz high speed, as shown in Figure 8, flicker becomes gradually and is difficult to identification.Particularly, when making the driving frequency of 1 group of T be 120Hz, flicker just can not be identified.Therefore, if improve the response characteristic of peripheral driving circuit, TFT20 and liquid crystal etc., the flicker of just can forgetting it, making frame rate is more than the 120Hz, and the improvement center that drives the HT method is set in low gray scale side.In this case, consider and combination for the such HT method of the capacitively coupled HT method that can set the threshold voltage difference in 1 pixel at the high gray scale side center that improves.

For example, as the condition of capacitively coupled HT method, the pixel electrode 17 that the plain B of secondary image goes up formation forms and accounts for the area of the pixel total area more than 50%.As the condition that drives the HT method, the ratio (frame ratio) that exists of high gray scale frame and low gray scale frame is n: 1 (n 〉=1) drives like that.Because the ratio of the plain B of the secondary image of the high threshold voltage in the display frame increases, therefore utilize capacitively coupled HT method that the improvement center of viewing angle characteristic is set in low gray scale side.Again, utilize to drive during the high luminance frame that the HT method makes bright briliancy longlyer than the image duration of the low briliancy of dark briliancy, therefore high gray scale side is improved.To be to improve viewing angle characteristic in the zone widely with the result that driving HT method is made up in the capacitively coupled HT method under such condition.The frame of high luminance frame and low luminance frame than (T1: T2) can certainly be at T1: T2=1: after 1 not discreteness be adjusted into T1: T2=1: 2, and be adjusted into T1: T2=1: 1.1.

Again, as other conditions of capacitively coupled HT method, the pixel electrode 17 that the plain B of secondary image goes up formation forms and accounts for the area of the pixel total area below 50%.As the condition that drives the HT method, high gray scale frame and low gray scale frame to have ratio (frame compares) be 1: n drives (n 〉=1).Because the ratio of the plain A of the secondary image of the low threshold voltage in the capacitive coupling HT method, display frame increases, so the improvement center of viewing angle characteristic is set in high gray scale side.Again, owing to drive the HT method, than short during the low luminance frame of dark briliancy, therefore low gray scale improves during the high luminance frame of bright briliancy.To be to improve viewing angle characteristic in the gray areas widely with the result that driving HT method is made up in the capacitively coupled HT method under such condition.The frame of high luminance frame and low luminance frame than (T1: T2) can certainly be at T1: T2=1: after 1 not discreteness be adjusted into T1: T2=1: 2, and be adjusted into T1: T2=1: 1.1.Again,, be improved, can access liquid crystal indicator than the high briliancy of liquid crystal indicator of the foregoing description 1 and embodiment 2 for the transmissivity of the pixel of same grayscale voltage because the ratio of the plain A of the secondary image of the low threshold voltage in the display frame increases.

Example 2

With Figure 18 and Figure 19 the liquid crystal indicator of the 2nd example of the present invention is described below.The liquid crystal indicator of this example possesses the pixel group PGin that the area of pixel electrode (the 1st pixel electrode) 16 and pixel electrode (the 2nd pixel electrode) 17 constitutes than different a plurality of pixels.Figure 18 represents 27 pixels in a plurality of pixels of rectangular configuration of liquid crystal indicator of this example.As shown in figure 18, be formed on side by side on the glass substrate 10 mutually at upwardly extending many grid bus Gm of right and left among the figure.Intersect across dielectric film (not illustrating) on grid bus Gm, many drain electrode bus Drn, Dgn, Dbn of above-below direction extension form mutually side by side in the drawings.

Each crossover location at grid bus Gm and drain bus Drn, Dgn, Dbn nearby disposes TFT20 respectively.The gate electrode of each TFT20 (G) is electrically connected respectively at grid bus Gm, and drain electrode (D) is electrically connected respectively at drain electrode bus Drn, Dgn, Dbn.Source electrode (S) is electrically connected on the pixel electrode 16 in the

pixel electrode

16,17 that separately forms on each pixel Prmn, Pgmn, Pbmn across control electrode 25.

The formation as described below bus that respectively drains, the bus that promptly drains Dr1 drives red (R) pixel Pr11, Pr21, Pr31, and drain electrode bus Dg1 drives green (G) pixel Pg11, Pg21, Pg31, and drain electrode bus Db1 drives blue (B) pixel Pb11, Pb21, Pb31.Below identical, drain electrode bus Drn drives R pixel Prmn, drain electrode bus Dgn drives G pixel Pgmn, drain electrode bus Dbn drives B pixel Prmn ground formation.Pixel Prmn, Pgmn, Pbmn have secondary image element (the 1st secondary image element) A that forms pixel electrode 16 and secondary image element (the 2nd pixel) B that forms pixel electrode 17.Pixel electrode 17 with and control electrode 25 between clip dielectric film and form control capacitance (electric capacity of regulation) Cc.

Pixel group PG11 has 9 pixel Pr11～Pr31, Pg11～Pg31, the Pb11～Pb31 of rectangular configuration.Equally, pixel group PGin has 9 pixels.

The area ratio that pixel group PG11 has a

pixel electrode

16,17 is formed into 1: 9 pixel Pr21, Pg11, Pb31 (the 1st pixel), area to be likend and likens to 4: 6 pixel Pr31, Pg21, Pb11 (the 3rd pixel) to 2: 8 pixel Pr11, Pg31, Pb21 (the 2nd pixel) and area.Below identical, pixel group Pgin has these 3 pixels of the 1st～the 3rd pixel respectively.On drain electrode bus Dr1, Dg1, Db1, connect the 1st～the 3rd pixel electrode respectively.By means of this, the total area separately of the

pixel electrode

16,17 of the total area separately of the

pixel electrode

16,17 of separately the total area of the

pixel electrode

16,17 of R pixel Pr11, Pr21, Pr31, G pixel Pg11, Pg21, Pg31 and B pixel Pb11, Pb21, Pb31 equates in pixel group PG11.Below identical, in pixel group PGin, each total area of the

pixel electrode

16,17 that forms respectively in R pixel, G pixel and the B pixel equates.

With the subtend glass substrate (not shown) of glass substrate 10 subtends configurations on almost whole on, form CF resin bed and common electrode (all not shown) in order.The liquid crystal layer that utilizes common electrode,

pixel electrode

16,17 and wherein clip forms liquid crystal capacitance C1c1, C1c2 on each pixel Prmn, Pgmn, Pbmn.Glass substrate 10 and liquid crystal capacitance C1c2 between the subtend glass substrate binding of connecting with control capacitance Cc.By means of this, on pixel Prmn, Pgmn, Pbmn, form the different secondary image of threshold voltage plain A, B.

Figure 19 represents the curve map of the viewing angle characteristic of VA type liquid crystal indicator.The gray scale of transverse axis presentation video data, the longitudinal axis is represented the γ value.Link among the figure ◆ the characteristic on the frontal of the liquid crystal indicator of this example of curve representation of mark.The curve representation that links the mark among the figure is the characteristic of tilted direction of the liquid crystal indicator of the 1st pixel that forms at 1: 9 with the area ratio of

pixel electrode

16,17 only, and the curve representation that links the △ mark among the figure only is the characteristic of tilted direction of the liquid crystal indicator of the 2nd pixel that forms at 2: 8 with the area ratio of pixel electrode 16,17.The curve representation of binding * mark is the characteristic of tilted direction of the liquid crystal indicator of the 3rd pixel that forms at 4: 6 with the area ratio of

pixel electrode

16,17 only among the figure, links among the figure ● the characteristic of the tilted direction of the liquid crystal indicator of this example of curve representation of mark.Curve representation among the figure shown in the dotted line does not use the characteristic of tilted direction of the existing VA type liquid crystal indicator of capacitive coupling HT method.Among Figure 19, each viewing angle characteristic of tilted direction is measured the γ value of the part of each gray scale again for the γ value with the frontal more than 96 gray scales is set at 2.4.

As shown in figure 19, when the area of

pixel electrode

16,17 than not simultaneously, can improve viewing angle characteristic the gray areas difference (with reference to mark, △ mark, * mark).Have by the area of the plain B of the secondary image of capacity coupled pixel electrode 17 more for a short time, the gray area of improvement is more to high gray scale side shifting.The area of

pixel electrode

16,17 disperses to have the tonal range additive process that can improve in the viewing area than different a plurality of pixel Prmn, Pgmn, Pbmn.Therefore viewing angle characteristic equalization on macroscopic view is in the tonal range internal characteristic of broadness improve (reference ● mark).The γ value of liquid crystal indicator is being more than 1 from low gray scale side (32 gray scale) in the wide scope of high gray scale side (255 gray scale) always.Owing to different HT technology (driving HT method and capacitive coupling HT method) is made up, therefore can't be sought degree ground raising viewing angle characteristic as the liquid crystal indicator of above-mentioned example 1.But it is narrow and small that the liquid crystal indicator of this example can improve amendatory gray areas, the existing problems of capacitive coupling HT method.

As mentioned above, improve area with

pixel electrode

16,17 than different a plurality of pixel Prmn, Pgmn, Pbmn decentralized configuration in the viewing area, the viewing angle characteristic of each pixel Prmn, Pgmn, Pbmn is synthesized on macroscopic view.Therefore, the viewing angle characteristic of liquid crystal indicator is improved in vast gray areas.Therefore viewing angle characteristic is on average improved, and when watching animation display such as TV image, can access superior display quality.

Example 3

Below, with Figure 20 and Figure 21 the liquid crystal indicator of the 3rd example of the present invention is described.The liquid crystal indicator of this example is characterized in that possessing the pixel group that is made of the different a plurality of pixels of the capacitance of control capacitance (regulation electric capacity).Figure 20 represents the equivalent electrical circuit of 4 pixels in a plurality of pixels of rectangular configuration of liquid crystal indicator of this example.As shown in figure 20, upwardly extending many grid buss 12 of right and left are formed on the glass substrate mutually side by side among the figure.Intersect across dielectric film 30 on grid bus 12, upwardly extending many drain electrode buses 14 of upper and lower form mutually side by side in the drawings.

Each crossover location in grid bus 12 and drain electrode bus 14 nearby disposes TFT20 respectively.The gate electrode of each TFT20 (G) is electrically connected respectively at grid bus 12.Drain electrode (D) is electrically connected respectively in drain electrode bus 14.Again, the pixel region that crosscut delimited by grid bus 12 and drain electrode bus 14 forms the storage capacitance bus 18 that extends side by side with grid bus 12.On storage capacitance bus 18, on each pixel, form storage capacitance electrode (target) 19 across dielectric film 30.Store capacitance electrode 19 and be electrically connected source electrode (S) at TFT20 by control electrode 25.The dielectric film 30 formation storage capacitor C s that utilize and store capacitance electrode 18, store capacitance electrode 19 and between them, clip.

The pixel region of being delimited by grid bus 12 and drain electrode bus 14 is split into secondary image element (the 1st secondary image element) A and secondary image element (the 2nd secondary image element) B.On the plain A of secondary image, form pixel electrode (the 1st pixel electrode) 16, on the plain B of secondary image, form the pixel electrode (the 2nd pixel electrode) 17 that separates with pixel electrode 16.The area ratio of

pixel electrode

16,17 formed 3: 7.Pixel electrode 16 is electrically connected at the source electrode (S) of storing capacitance electrode 19 and TFT20.Utilize pixel electrode 17, control electrode 25 to reach and form control capacitances at 17,15 diaphragms that clip of two electrodes 32.Pixel electrode 17 utilizes the capacitive coupling of control capacitance to be connected source electrode (S) indirectly.Pixel electrode 17 becomes electric quick condition.

In Figure 20, the capacitance of the control capacitance that forms on the pixel that is disposed at upper left and bottom right and the pixel that is disposed at upper right and lower-left is different.On the pixel that is disposed at upper left and bottom right, form control capacitance Cc1, on the pixel that is disposed at upper right and lower-left, form control capacitance Cc2.By for example in the pixel of pixel that forms control capacitance Cc1 and formation control capacitance Cc2, changing the area of control electrode 25, can change capacitance.Like this, pixel group 39 just has a plurality of (among Figure 20 being 4) pixel of the control capacitance Cc1, the Cc2 that possess different capacitances.

With the opposed glass substrate of glass substrate subtend configuration on, form CF resin bed (not shown) and common electrode 42 in order.Utilize the pixel electrode 16, common electrode 42 of the plain A of secondary image and form liquid crystal capacitance C1c1 at 16,42 liquid crystal layers that clip of two electrodes 6.Pixel electrode 17,

common electrode

42 and 17,42 liquid crystal layers that clip of two electrodes 6 that utilization has the plain B of secondary image of control capacitance Cc1 form liquid crystal capacitance C1c2, utilize pixel electrode 17,

common electrode

42 and 17,42 liquid crystal layers that clip of two electrodes 6 of the plain B of secondary image with control capacitance Cc2 to form liquid crystal capacitance C1c2.Control capacitance Cc1 and liquid crystal capacitance C1c2 are connected in series between glass substrate 10 and opposed glass substrate.Equally, control capacitance Cc2 and liquid crystal capacitance C1c2 are connected in series between glass substrate 10 and opposed glass substrate.

When TFT20 was conducting state, the grayscale voltage that is applied to drain electrode bus 14 was applied to pixel electrode 16 by TFT20, applies voltage Vpx1 on the liquid crystal layer 6 of the plain A of secondary image.Therefore at this moment, cut apart voltage Vpx1, on the pixel electrode 17 of the plain B of the secondary image with control capacitance Cc1, apply the voltage different with pixel electrode 16 according to the capacity ratio of liquid crystal capacitance C1c2 and control capacitance Cc1.The voltage Vpx21 that applies on the liquid crystal layer 6 of the plain B of secondary image can as described belowly represent, promptly

Vpx21＝(Cc1/(C1c2+Cc1))×Vpx1…(3)

Equally, the voltage Vpx22 that applies on the liquid crystal layer 6 of the plain B of the secondary image with control capacitance Cc2 can as described belowly represent, promptly

Vpx22＝(Cc2/(C1c2+Cc2))×Vpx1…(4)

Set capacitance, making the voltage ratio Vpx21/Vpx1 of the pixel with control capacitance Cc1 is 0.8 in middle gray (127 gray scale).Again, set capacitance, making the voltage ratio Vpx22/Vpx1 of the pixel with control capacitance Cc1 is 0.59 in middle gray (127 gray scale).Like this, the viewing area of liquid crystal indicator forms the structure that has the pixel group 39 that is made of the pixel that possesses the different secondary image element of threshold voltage difference.

Figure 21 represents the curve map of the viewing angle characteristic of VA type liquid crystal indicator.Transverse axis is represented the gray scale of display image data, and the longitudinal axis is represented the γ value.Link among the figure ◆ the characteristic on the frontal of the liquid crystal indicator of this example of curve representation of mark.The curve representation that links the mark among the figure forms the characteristic of tilted direction that the control capacitance that makes whole pixels is the liquid crystal indicator of control capacitance Cc1, and the control capacitance that the curve representation that links the △ mark among the figure forms whole pixels is the characteristic of tilted direction of the liquid crystal indicator of control capacitance Cc2.The characteristic of tilted direction of liquid crystal indicator that links this example of curve representation of ■ mark among the figure, the curve representation among the figure shown in the dotted line are not used the characteristic of tilted direction of the existing VA type liquid crystal indicator of capacitive coupling HT method.Among Figure 21, each viewing angle characteristic of tilted direction is to be set at after 2.4 in the γ value with the frontal more than 96 gray scales to measure the γ value of the part of each gray scale.

As shown in figure 21, change the capacitance of control capacitance Cc1, Cc2, make voltage ratio Vpx21/Vpx1, Vpx22/Vpx1 difference, therefore can improve the gray areas difference (with reference to mark, △ mark) of viewing angle characteristic.It is more little that this voltage ratio becomes, and the gray areas of improvement is shifted to high gray scale side more.A plurality of pixels that voltage ratio Vpx21/Vpx1, Vpx22/Vpx1 are different disperse to exist in the viewing area, therefore the tonal range addition that can improve.Make viewing angle characteristic equalization on macroscopic view with this, at vast tonal range internal characteristic improve (with reference to the ■ mark).The γ value of liquid crystal indicator is remaining on more than 1 in the vast scope of high gray scale side (255 gray scale) from low gray scale side (32 gray scale).Identical with above-mentioned the 2nd example, because different HT technology (driving HT method and capacitive coupling HT method) is made up, therefore can not seek as the liquid crystal indicator of above-mentioned the 1st example, to improve viewing angle characteristic.But the liquid crystal indicator of this example can improve the existing problems of the narrow and small capacitive coupling HT method of amendatory gray areas.

As mentioned above, improve the capacitance that changes control capacitance Cc1, Cc2, make the different a plurality of pixels decentralized configuration in the viewing area of voltage ratio Vpx21/Vpx1, Vpx22/Vpx1, on macroscopic view that the viewing angle characteristic of each pixel is synthetic.By means of this, the viewing angle characteristic of liquid crystal indicator is improved in vast gray areas, therefore can access superior display quality.

The present invention is not limited to above-mentioned example, can have various distortion.

The liquid crystal indicator of above-mentioned example 2 is formed in the whole identical devices of capacitance of the control capacitance Cc of each pixel, but the invention is not restricted to this.For example, the capacitance of the Cc of the control capacitance of any one pixel Prmn, Pgmn of pixel group PGin, Pbmn also can be different with this capacitance of remaining pixel Prmn, Pgmn, Pbmn.Or the Cc capacitance of the control capacitance that forms among pixel Prmn, Pgmn, the Pbmn also can have nothing in common with each other.In this case, can obtain and the above-mentioned the 2nd and the 3rd identical effect of example.

The liquid crystal indicator of above-mentioned the 3rd example is formed on the area of

pixel electrode

16,17 on whole pixels than identical, but the invention is not restricted to this.For example, any one pixel in the pixel group 39 also can be that the area of

pixel electrode

16,17 is than different with remaining pixel.Or also can be that the area ratio of

pixel electrode

16,17 of each pixel of pixel group 39 has nothing in common with each other.In this case, can obtain and the above-mentioned the 2nd and the 3rd identical effect of example.

The above-mentioned the 2nd and the liquid crystal indicator of the 3rd example in, only use capacitive coupling HT method, but the invention is not restricted to this.The for example above-mentioned the 2nd and the liquid crystal indicator of the 3rd example in can certainly use the HT method that drives.Also can the area of the 1st and the 2nd pixel electrode than or different each pixel of the capacitance of control capacitance Cc on distribute high luminance frame and low luminance frame, the relation of the voltage that applies on the gray-scale value that makes input image data and each pixel is different.In this case, also can obtain and the identical effect of above-mentioned the 1st example.

The liquid crystal indicator of above-mentioned the 1st～the 3rd example is that example describes with VA type (MVA type) liquid crystal indicator, but the invention is not restricted to this.Even the liquid crystal indicator of TN mode also can be obtained the effect identical with above-mentioned example.

Claims

1. a liquid crystal indicator is characterized in that having

Be sealed in the liquid crystal between opposed a pair of substrate;

A plurality of pixels of rectangular configuration on a side of described a pair of substrate;

The thin film transistor (TFT) that forms in described each pixel;

To be made up with the low luminance frame that drives described pixel with the briliancy lower to drive the high luminance frame of described pixel than the higher briliancy of regulation briliancy corresponding to the gray-scale value of input image data than the briliancy of described regulation, the briliancy that determines the described pixel in the described high luminance frame is that the briliancy of the described pixel in bright briliancy and the described low luminance frame is dark briliancy, and described high luminance frame and described low luminance frame have a ratio so that obtain the image processing part of the briliancy that equates with described regulation briliancy;

The 1st secondary image element that in described pixel, forms; And

Separate with described the 1st secondary image element and to be formed on the 2nd secondary image element in the described pixel, that obtain the briliancy lower than the briliancy of the plain per unit area of described the 1st secondary image.

2. liquid crystal indicator according to claim 1 is characterized in that,

Described pixel has

Source electrode by control electrode and described thin film transistor (TFT) is electrically connected, the 1st pixel electrode that on described the 1st secondary image element, forms and

And described control electrode between clip the electric capacity that dielectric film forms regulation, separate the 2nd pixel electrode that is formed on described the 2nd secondary image element with described the 1st pixel electrode.

3. liquid crystal indicator according to claim 1 is characterized in that,

With from becoming maximum briliancy the optical characteristics of direction detection of predetermined angular to be T, to be ta, to be tb, described briliancy ta and described briliancy tb and the ratio of described maximum briliancy T is respectively Ta and Tb with briliancy based on gray-scale value b with the briliancy based on gray-scale value a of coming from the direction identical with the angle of regulation with the normal direction of display frame, during γ={ log (Ta)-log (Tb) }/{ log (a)-log (b) }

Described γ value is not maximum gray-scale value α when described image processing part is not handled the described pixel of described input image data ground driving, and handle described view data at described image processing part, described γ value is maximum when only driving the pixel that is made of described the 1st secondary image element gray-scale value β is inconsistent, wherein, a is different values with b.

4. liquid crystal indicator according to claim 3 is characterized in that,

Described gray-scale value β is than the big value of described gray-scale value α.

5. liquid crystal indicator according to claim 2 is characterized in that,

Driving display device as described below, promptly described the 2nd pixel electrode forms the area more than 50% of the total area that accounts for described pixel, and the described ratio that exists of described high luminance frame and described low luminance frame is n: 1, n 〉=1 wherein.

6. liquid crystal indicator according to claim 2 is characterized in that,

Driving display device as described below, promptly described the 2nd pixel electrode forms the area below 50% of the total area that accounts for described pixel, and the described ratio that exists of described high luminance frame and described low luminance frame is 1: n, wherein n 〉=1.

7. liquid crystal indicator according to claim 1 is characterized in that,

Described image processing part by in be contained in control circuit, the driving circuit of the drain electrode bus that the driving circuit of the grid bus that this control circuit is electrically connected the gate electrode that drives with described thin film transistor (TFT) and the drain electrode of driving and described thin film transistor (TFT) are electrically connected is controlled.

8. liquid crystal indicator according to claim 1 is characterized in that,

Have the greyscale transformation table, this greyscale transformation table possesses high briliancy side gray-scale value that the briliancy of stating clearly that obtains in the described high luminance frame uses and obtains the low briliancy side gray-scale value that the described dark briliancy in the described low luminance frame is used.

9. liquid crystal indicator according to claim 8 is characterized in that,

Described greyscale transformation table is stored in memory circuit.

10. liquid crystal indicator according to claim 9 is characterized in that,

Be contained in control circuit in the described memory circuit, the driving circuit of the drain electrode bus that the driving circuit of the grid bus that this control circuit is electrically connected the gate electrode that drives with described thin film transistor (TFT) and the drain electrode of driving and described thin film transistor (TFT) are electrically connected is controlled.

11. liquid crystal indicator according to claim 2 is characterized in that,

The opposing party of described a pair of substrate have common electrode,

According to the electric capacity of the liquid crystal capacitance that between described the 2nd pixel electrode and described common electrode, forms and the electric capacity of, this liquid crystal capacitance and described regulation and volume ratio, generate the voltage that is applied to described liquid crystal capacitance.

12. liquid crystal indicator according to claim 1 is characterized in that,

Described liquid crystal has negative dielectric constant anisotropy, has the orientation perpendicular to real estate when not applying voltage.